DIGITAL CLOCK
In this activity I’ve made a
digital clock with Arduino, a RTC module and a module of four 7 segment
display.
 |
| Arduino UNO with the RTC and the diplay module |
COMPONENTS
1 x Arduino board
1 x USB cable
1 x RTC module
1 x four 7-segments display
module
17 x Wires
The Real Time Counter is
connected to Arduino by the bus I2C. This issue is very easy with the library “Wire.h” that provide the Arduino IDE. At
the beginning of the program, the code gets the date from this module and is
printed on the serial monitor. Then, in the loop function, the uC asks to the
RTC what hour is. The hour is in seconds, minutes and hours. This
information is displayed with the 7-segment module.
 |
| I2C RTC DS1307 Real Time Clock Module and 4X LED Display Digital Tube Module for Arduino buy on Deal Extreme |
The hour, minutes and seconds is obtained from the RTC with integer variables in the lines:
hora=now.hour();
minuto=now.minute();
segundo=now.second();
minuto=now.minute();
segundo=now.second();
One display can only show one digit, however, the numbers can have two digit. It is necessary to split these numbers
in single digits. The following lines solve this problem.
//For showing the hour and the minutes. For instance:19:50
int
numeros[]={hora/10,hora-10*(hora/10),minuto/10,minuto-10*(minuto/10)};
//For showing the
minutes and seconds
//int
numeros[]={minuto/10,minuto-10*(minuto/10),segundo/10,segundo-10*(segundo/10)};
For example, if hora=9 and minuto=43, numeros[] will be:
numeros[0]=hora/10=9/10=0
numeros[1]=hora-10*(hora/10)=9-10*(9/10)=9-10*(0)=9-0=9
numeros[2]=minuto/10=43/10=4
numeros[3]=minuto-10*(minuto/10)=43-10*(43/10)=43-10*(4)=43-40=3
Finally, the displays will show
the digits: 0,9,4,3
The module of 7-segment displays is connected to Arduino using one wire to 5 volts and twelve wires to the digital outputs. Four of them are for switching on/off each displays. The other eight outputs are used for controlling the seven segments and the dot. All the leds are shared by the displays and must be 'multiplexed' with D1-4 for controlling the switching on of each display of 7 segments.
 |
| Name of the leds in the displays of 7 segment |
#define D4 13
#define D3 12
#define D2 11
#define D1 10
#define LED_a 9
#define LED_b 8
#define LED_c 7
#define LED_d 6
#define LED_e 5
#define LED_f 4
#define LED_g 3
#define LED_dp 2
RESULTS
In the following video it is displayed the code of the Appendix 1. Here you can see a digital clock that only shows the minutes and seconds.
In the following video it is displayed the code of the Appendix 1. Here you can see a digital clock that only shows the minutes and seconds.
I've added another code in the Appendix 2 that scrolls a number of four digits in both directions. Also, there are others functions that show a number permanently or blink a number of four digits. In the next video you are going to see the scroll to
the right and to the left of two numbers of four digits.
REFERENCES
APPENDIX 1
Arduino main code:
#include <Wire.h>
#include <RTC.h>
#define D4 13
#define D3 12
#define D2 11
#define D1 10
#define LED_a 9
#define LED_b 8
#define LED_c 7
#define LED_d 6
#define LED_e 5
#define LED_f 4
#define LED_g 3
#define LED_dp 2
boolean
seven_seg_digits[10][8] = {{1,1,1,1,1,1,0,0},
// = 0
{0,1,1,0,0,0,0,0}, // = 1
{1,1,0,1,1,0,1,0}, // = 2
{1,1,1,1,0,0,1,0}, // = 3
{0,1,1,0,0,1,1,0}, // = 4
{1,0,1,1,0,1,1,0}, // = 5
{1,0,1,1,1,1,1,0}, // = 6
{1,1,1,0,0,0,0,0}, // = 7
{1,1,1,1,1,1,1,0}, // = 8
{1,1,1,0,0,1,1,0}, // = 9
};
// RTC
class based on the DS1307 chip connected via I2C and the Wire library
RTC_DS1307 RTC;
//Simple
general-purpose date/time class
DateTime now;
//Initializing
the variables
char
Date[15],Hour[15];
int
hora,minuto,segundo;
void setup()
{
Serial.begin(9600); //
Set serial out for debugging
pinMode(2, OUTPUT);//LED_dp
pinMode(3, OUTPUT);//LED_g
pinMode(4, OUTPUT);//LED_f
pinMode(5, OUTPUT);//LED_e
pinMode(6, OUTPUT);//LED_d
pinMode(7, OUTPUT);//LED_c
pinMode(8, OUTPUT);//LED_b
pinMode(9, OUTPUT);//LED_a
pinMode(10, OUTPUT);//D1
pinMode(11, OUTPUT);//D2
pinMode(12, OUTPUT);//D3
pinMode(13, OUTPUT);//D4
//Clear the four
display
digitalWrite(D1,HIGH);//D1 OFF
digitalWrite(D2,HIGH);//D2 OFF
digitalWrite(D3,HIGH);//D3 OFF
digitalWrite(D4,HIGH);//D4 OFF
RTCInit();//Initializes
the RTC module
delay(1000);
}
void loop()
{
now = RTC.now();//Reading
the current date and the hour
hora=now.hour();
minuto=now.minute();
segundo=now.second();
sprintf(Hour,"Hour= %d:%d:%d",hora,minuto,segundo);
Serial.println(Hour);
//For showing the hour
and the minutes. ej:19:50
//int
numeros[]={hora/10,hora-10*(hora/10),minuto/10,minuto-10*(minuto/10)};
//For
showing the minutes and seconds
int numeros[]={minuto/10,minuto-10*(minuto/10),segundo/10,segundo-10*(segundo/10)};
for(int i=0;i<4;i++)
{
digitalWrite(10+i,LOW);
for (byte
segCount = 0; segCount < 8; ++segCount)
{
digitalWrite(9-segCount,!seven_seg_digits[numeros[i]][segCount]);
if(i==1)
digitalWrite(LED_dp,LOW);//The second dot bright
}
delay(5);
}
}
void RTCInit(void)
{
Wire.begin();
RTC.begin();
RTC.adjust(DateTime(__DATE__, __TIME__));
delay(10);//A
moment for the uC breathes a little
now = RTC.now();
//Prepararing a
string of characters for debugging
sprintf(Date,"Date:%d/%d/%d",now.day(),now.month(),now.year()-2000);//Format:3/10/12
Serial.println(Date);
Serial.println();
}
#include <Wire.h>
#include <RTC.h>
#define D4 13
#define D3 12
#define D2 11
#define D1 10
#define LED_a 9
#define LED_b 8
#define LED_c 7
#define LED_d 6
#define LED_e 5
#define LED_f 4
#define LED_g 3
#define LED_dp 2
#define LEDred 1
#define BUZZER 0
boolean
seven_seg_digits[10][8] = {{1,1,1,1,1,1,0,0},
// = 0
{0,1,1,0,0,0,0,0}, // = 1
{1,1,0,1,1,0,1,0}, // = 2
{1,1,1,1,0,0,1,0}, // = 3
{0,1,1,0,0,1,1,0}, // = 4
{1,0,1,1,0,1,1,0}, // = 5
{1,0,1,1,1,1,1,0}, // = 6
{1,1,1,0,0,0,0,0}, // = 7
{1,1,1,1,1,1,1,0}, // = 8
{1,1,1,0,0,1,1,0}, // = 9
};
void setup()
{
Serial.begin(9600);//Initilizes
serial port
pinMode(0, OUTPUT);//Buzzer
pinMode(1, OUTPUT);//Red
led
pinMode(2, OUTPUT);//LED_dp
pinMode(3, OUTPUT);//LED_g
pinMode(4, OUTPUT);//LED_f
pinMode(5, OUTPUT);//LED_e
pinMode(6, OUTPUT);//LED_d
pinMode(7, OUTPUT);//LED_c
pinMode(8, OUTPUT);//LED_b
pinMode(9, OUTPUT);//LED_a
pinMode(10, OUTPUT);//D1
pinMode(11, OUTPUT);//D2
pinMode(12, OUTPUT);//D3
pinMode(13, OUTPUT);//D4
//Clear the four
display
digitalWrite(D1,HIGH);//D1 OFF
digitalWrite(D2,HIGH);//D2 OFF
digitalWrite(D3,HIGH);//D3 OFF
digitalWrite(D4,HIGH);//D4 OFF
delay(1000);
}
void loop()
{
//DisplayNumber(2734,5,0);//Display
a permanent number with 5 ms of delay
//delay(1000);//If the second variable is near to zero, the number will be static
//DisplayNumber(3451,200,0);//Display
a permanent number with 200 ms of delay
//delay(1000);
//DisplayNumber(1512,200,1);//The same as before but move the numbers to the right
//delay(1000);
LeftScroll(1234,200);//Scroll
left
//delay(1000);
//RightScroll(8654,200);//Scroll
right
//delay(1000);
//blinkNumber(4721,100);//
}
int * extractDigit(int numero)
{
int millares=numero/1000;
int centenas=(numero-1000*millares)/100;
int decenas=(numero-1000*millares-100*centenas)/10;
int
unidades=(numero-1000*millares-100*centenas-10*decenas);
static int
digitos[4]={millares,centenas,decenas,unidades};
//‘static’ es la puta clave para pasar el array
return digitos;
}
void
sevenSegWrite(byte digit)
{
for (byte
segCount = 0; segCount < 8; ++segCount)
{
digitalWrite(9-segCount,!seven_seg_digits[digit][segCount]);
}
}
void DisplayNumber(int numero,int
scrollSpeed,int direccion)
{
int millares=numero/1000;
int centenas=(numero-1000*millares)/100;
int decenas=(numero-1000*millares-100*centenas)/10;
int
unidades=(numero-1000*millares-100*centenas-10*decenas);
int numeros[]={millares,centenas,decenas,unidades};
if(direccion==1)//left to right
{
for(int i=0;i<4;i++)
{
digitalWrite(10+i,LOW);
sevenSegWrite(numeros[i]);
delay(scrollSpeed);
digitalWrite(10+i,HIGH);
}
}
{
for(int i=3;i>=0;i--)
{
digitalWrite(10+i,LOW);
sevenSegWrite(numeros[i]);
delay(scrollSpeed);
digitalWrite(10+i,HIGH);
}
}
}
void LeftScroll(int numero,int
scrollSpeed)
{
int *numeros;
numeros=
extractDigit(numero);
delay(6000);
for(int i=3;i>=0;i--)
{
digitalWrite(10+i,LOW);
sevenSegWrite(*(numeros+i));
delay(scrollSpeed);
digitalWrite(10+i,HIGH);
}
}
void RightScroll(int numero,int
scrollSpeed)
{
int * numeros
= extractDigit(numero);
for(int i=0;i<4;i++)
{
digitalWrite(10+i,LOW);
sevenSegWrite(*(numeros+i));
delay(scrollSpeed);
digitalWrite(10+i,HIGH);
}
}
void blinkNumber(int numero,int
blinkSpeed)
{
int * numeros
= extractDigit(numero);
for(int i=0;i<4;i++)
{
digitalWrite(10+i,LOW);
sevenSegWrite(*(numeros+i));
delay(2);
digitalWrite(10+i,HIGH);
}
delay(blinkSpeed);
for(int i=0;i<4;i++)
{
digitalWrite(10+i,LOW);
sevenSegWrite(*(numeros+i));
delay(2);
digitalWrite(10+i,HIGH);
}
}
